import functools

from matplotlib import artist as martist, transforms as mtransforms
from matplotlib.axes import subplot_class_factory
from matplotlib.transforms import Bbox
from .mpl_axes import Axes

import numpy as np


class ParasiteAxesBase:

    def get_images_artists(self):
        artists = {a for a in self.get_children() if a.get_visible()}
        images = {a for a in self.images if a.get_visible()}

        return list(images), list(artists - images)

    def __init__(self, parent_axes, **kwargs):
        self._parent_axes = parent_axes
        kwargs["frameon"] = False
        super().__init__(parent_axes.figure, parent_axes._position, **kwargs)

    def cla(self):
        super().cla()

        martist.setp(self.get_children(), visible=False)
        self._get_lines = self._parent_axes._get_lines

        # In mpl's Axes, zorders of x- and y-axis are originally set
        # within Axes.draw().
        if self._axisbelow:
            self.xaxis.set_zorder(0.5)
            self.yaxis.set_zorder(0.5)
        else:
            self.xaxis.set_zorder(2.5)
            self.yaxis.set_zorder(2.5)


@functools.lru_cache(None)
def parasite_axes_class_factory(axes_class=None):
    if axes_class is None:
        axes_class = Axes

    return type("%sParasite" % axes_class.__name__,
                (ParasiteAxesBase, axes_class), {})


ParasiteAxes = parasite_axes_class_factory()


class ParasiteAxesAuxTransBase:
    def __init__(self, parent_axes, aux_transform, viewlim_mode=None,
                 **kwargs):
        self.transAux = aux_transform
        self.set_viewlim_mode(viewlim_mode)
        super().__init__(parent_axes, **kwargs)

    def _set_lim_and_transforms(self):

        self.transAxes = self._parent_axes.transAxes

        self.transData = \
            self.transAux + \
            self._parent_axes.transData

        self._xaxis_transform = mtransforms.blended_transform_factory(
                self.transData, self.transAxes)
        self._yaxis_transform = mtransforms.blended_transform_factory(
                self.transAxes, self.transData)

    def set_viewlim_mode(self, mode):
        if mode not in [None, "equal", "transform"]:
            raise ValueError("Unknown mode: %s" % (mode,))
        else:
            self._viewlim_mode = mode

    def get_viewlim_mode(self):
        return self._viewlim_mode

    def update_viewlim(self):
        viewlim = self._parent_axes.viewLim.frozen()
        mode = self.get_viewlim_mode()
        if mode is None:
            pass
        elif mode == "equal":
            self.axes.viewLim.set(viewlim)
        elif mode == "transform":
            self.axes.viewLim.set(
                viewlim.transformed(self.transAux.inverted()))
        else:
            raise ValueError("Unknown mode: %s" % (self._viewlim_mode,))

    def _pcolor(self, super_pcolor, *XYC, **kwargs):
        if len(XYC) == 1:
            C = XYC[0]
            ny, nx = C.shape

            gx = np.arange(-0.5, nx)
            gy = np.arange(-0.5, ny)

            X, Y = np.meshgrid(gx, gy)
        else:
            X, Y, C = XYC

        if "transform" in kwargs:
            mesh = super_pcolor(X, Y, C, **kwargs)
        else:
            orig_shape = X.shape
            xyt = np.column_stack([X.flat, Y.flat])
            wxy = self.transAux.transform(xyt)
            gx = wxy[:, 0].reshape(orig_shape)
            gy = wxy[:, 1].reshape(orig_shape)
            mesh = super_pcolor(gx, gy, C, **kwargs)
            mesh.set_transform(self._parent_axes.transData)

        return mesh

    def pcolormesh(self, *XYC, **kwargs):
        return self._pcolor(super().pcolormesh, *XYC, **kwargs)

    def pcolor(self, *XYC, **kwargs):
        return self._pcolor(super().pcolor, *XYC, **kwargs)

    def _contour(self, super_contour, *XYCL, **kwargs):

        if len(XYCL) <= 2:
            C = XYCL[0]
            ny, nx = C.shape

            gx = np.arange(0., nx)
            gy = np.arange(0., ny)

            X, Y = np.meshgrid(gx, gy)
            CL = XYCL
        else:
            X, Y = XYCL[:2]
            CL = XYCL[2:]

        if "transform" in kwargs:
            cont = super_contour(X, Y, *CL, **kwargs)
        else:
            orig_shape = X.shape
            xyt = np.column_stack([X.flat, Y.flat])
            wxy = self.transAux.transform(xyt)
            gx = wxy[:, 0].reshape(orig_shape)
            gy = wxy[:, 1].reshape(orig_shape)
            cont = super_contour(gx, gy, *CL, **kwargs)
            for c in cont.collections:
                c.set_transform(self._parent_axes.transData)

        return cont

    def contour(self, *XYCL, **kwargs):
        return self._contour(super().contour, *XYCL, **kwargs)

    def contourf(self, *XYCL, **kwargs):
        return self._contour(super().contourf, *XYCL, **kwargs)

    def apply_aspect(self, position=None):
        self.update_viewlim()
        super().apply_aspect()


@functools.lru_cache(None)
def parasite_axes_auxtrans_class_factory(axes_class=None):
    if axes_class is None:
        parasite_axes_class = ParasiteAxes
    elif not issubclass(axes_class, ParasiteAxesBase):
        parasite_axes_class = parasite_axes_class_factory(axes_class)
    else:
        parasite_axes_class = axes_class
    return type("%sParasiteAuxTrans" % parasite_axes_class.__name__,
                (ParasiteAxesAuxTransBase, parasite_axes_class),
                {'name': 'parasite_axes'})


ParasiteAxesAuxTrans = parasite_axes_auxtrans_class_factory(
    axes_class=ParasiteAxes)


class HostAxesBase:
    def __init__(self, *args, **kwargs):
        self.parasites = []
        super().__init__(*args, **kwargs)

    def get_aux_axes(self, tr, viewlim_mode="equal", axes_class=None):
        parasite_axes_class = parasite_axes_auxtrans_class_factory(axes_class)
        ax2 = parasite_axes_class(self, tr, viewlim_mode)
        # note that ax2.transData == tr + ax1.transData
        # Anthing you draw in ax2 will match the ticks and grids of ax1.
        self.parasites.append(ax2)
        ax2._remove_method = self.parasites.remove
        return ax2

    def _get_legend_handles(self, legend_handler_map=None):
        all_handles = super()._get_legend_handles()
        for ax in self.parasites:
            all_handles.extend(ax._get_legend_handles(legend_handler_map))
        return all_handles

    def draw(self, renderer):

        orig_artists = list(self.artists)
        orig_images = list(self.images)

        if hasattr(self, "get_axes_locator"):
            locator = self.get_axes_locator()
            if locator:
                pos = locator(self, renderer)
                self.set_position(pos, which="active")
                self.apply_aspect(pos)
            else:
                self.apply_aspect()
        else:
            self.apply_aspect()

        rect = self.get_position()

        for ax in self.parasites:
            ax.apply_aspect(rect)
            images, artists = ax.get_images_artists()
            self.images.extend(images)
            self.artists.extend(artists)

        super().draw(renderer)
        self.artists = orig_artists
        self.images = orig_images

    def cla(self):
        for ax in self.parasites:
            ax.cla()
        super().cla()

    def twinx(self, axes_class=None):
        """
        create a twin of Axes for generating a plot with a sharex
        x-axis but independent y axis.  The y-axis of self will have
        ticks on left and the returned axes will have ticks on the
        right
        """

        if axes_class is None:
            axes_class = self._get_base_axes()

        parasite_axes_class = parasite_axes_class_factory(axes_class)

        ax2 = parasite_axes_class(self, sharex=self, frameon=False)
        self.parasites.append(ax2)
        ax2._remove_method = self._remove_twinx

        self.axis["right"].set_visible(False)

        ax2.axis["right"].set_visible(True)
        ax2.axis["left", "top", "bottom"].set_visible(False)

        return ax2

    def _remove_twinx(self, ax):
        self.parasites.remove(ax)
        self.axis["right"].set_visible(True)
        self.axis["right"].toggle(ticklabels=False, label=False)

    def twiny(self, axes_class=None):
        """
        create a twin of Axes for generating a plot with a shared
        y-axis but independent x axis.  The x-axis of self will have
        ticks on bottom and the returned axes will have ticks on the
        top
        """

        if axes_class is None:
            axes_class = self._get_base_axes()

        parasite_axes_class = parasite_axes_class_factory(axes_class)

        ax2 = parasite_axes_class(self, sharey=self, frameon=False)
        self.parasites.append(ax2)
        ax2._remove_method = self._remove_twiny

        self.axis["top"].set_visible(False)

        ax2.axis["top"].set_visible(True)
        ax2.axis["left", "right", "bottom"].set_visible(False)

        return ax2

    def _remove_twiny(self, ax):
        self.parasites.remove(ax)
        self.axis["top"].set_visible(True)
        self.axis["top"].toggle(ticklabels=False, label=False)

    def twin(self, aux_trans=None, axes_class=None):
        """
        create a twin of Axes for generating a plot with a sharex
        x-axis but independent y axis.  The y-axis of self will have
        ticks on left and the returned axes will have ticks on the
        right
        """

        if axes_class is None:
            axes_class = self._get_base_axes()

        parasite_axes_auxtrans_class = \
            parasite_axes_auxtrans_class_factory(axes_class)

        if aux_trans is None:
            ax2 = parasite_axes_auxtrans_class(
                self, mtransforms.IdentityTransform(), viewlim_mode="equal")
        else:
            ax2 = parasite_axes_auxtrans_class(
                self, aux_trans, viewlim_mode="transform")
        self.parasites.append(ax2)
        ax2._remove_method = self.parasites.remove

        self.axis["top", "right"].set_visible(False)

        ax2.axis["top", "right"].set_visible(True)
        ax2.axis["left", "bottom"].set_visible(False)

        def _remove_method(h):
            self.parasites.remove(h)
            self.axis["top", "right"].set_visible(True)
            self.axis["top", "right"].toggle(ticklabels=False, label=False)
        ax2._remove_method = _remove_method

        return ax2

    def get_tightbbox(self, renderer, call_axes_locator=True):
        bbs = [ax.get_tightbbox(renderer, call_axes_locator)
               for ax in self.parasites]
        bbs.append(super().get_tightbbox(renderer, call_axes_locator))
        return Bbox.union([b for b in bbs if b.width != 0 or b.height != 0])


@functools.lru_cache(None)
def host_axes_class_factory(axes_class=None):
    if axes_class is None:
        axes_class = Axes

    def _get_base_axes(self):
        return axes_class

    return type("%sHostAxes" % axes_class.__name__,
                (HostAxesBase, axes_class),
                {'_get_base_axes': _get_base_axes})


def host_subplot_class_factory(axes_class):
    host_axes_class = host_axes_class_factory(axes_class=axes_class)
    subplot_host_class = subplot_class_factory(host_axes_class)
    return subplot_host_class


HostAxes = host_axes_class_factory(axes_class=Axes)
SubplotHost = subplot_class_factory(HostAxes)


def host_axes(*args, axes_class=None, figure=None, **kwargs):
    """
    Create axes that can act as a hosts to parasitic axes.

    Parameters
    ----------
    figure : `matplotlib.figure.Figure`
        Figure to which the axes will be added. Defaults to the current figure
        `pyplot.gcf()`.

    *args, **kwargs :
        Will be passed on to the underlying ``Axes`` object creation.
    """
    import matplotlib.pyplot as plt
    host_axes_class = host_axes_class_factory(axes_class)
    if figure is None:
        figure = plt.gcf()
    ax = host_axes_class(figure, *args, **kwargs)
    figure.add_axes(ax)
    plt.draw_if_interactive()
    return ax


def host_subplot(*args, axes_class=None, figure=None, **kwargs):
    """
    Create a subplot that can act as a host to parasitic axes.

    Parameters
    ----------
    figure : `matplotlib.figure.Figure`
        Figure to which the subplot will be added. Defaults to the current
        figure `pyplot.gcf()`.

    *args, **kwargs :
        Will be passed on to the underlying ``Axes`` object creation.
    """
    import matplotlib.pyplot as plt
    host_subplot_class = host_subplot_class_factory(axes_class)
    if figure is None:
        figure = plt.gcf()
    ax = host_subplot_class(figure, *args, **kwargs)
    figure.add_subplot(ax)
    plt.draw_if_interactive()
    return ax
